Drop impact analysis of smart unmanned aerial vehicle (SUAV) landing gear and comparison with experimental data

Kong, Jeong-Pyo; Lee, Y.S.; Han, J.D.; Ahn, Oh Sung

doi:10.1002/mawe.200900426

Cited by 4 publications

(2 citation statements)

References 7 publications

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“…In 2006, Lernbeiss and Plöch introduced an Multi-Body System (MBS)-based landing-gear model and investigated the numerical simulation of a simple static and dynamic load by comparing with a finite-element model [27]. In 2009, Kong et al conducted drop-impact analyses for the landing gear of smart unmanned aerial vehicles using the explicit finite-element code LS-DYNA [28]. Experimental data were used to revise the impact model for the landing gear.…”

Section: Nomenclaturementioning

confidence: 99%

Landing-Gear Drop-Test Rig Development and Application for Light Airplanes

Xue

Han

Wengang

et al. 2012

Journal of Aircraft

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A drop-test rig is developed for the landing gear of a light multifunctional amphibious airplane based on its drop-test specifications. Several key technologies (including the schematic design of the light-aircraft drop test, the control-system design for the drop test, the high-speed turn of the wheel, the accurate lifting of the drop system, design of the measuring platform, and the imitation of the runway) are studied. Simultaneously, the system can realize accurate measurement and conduct the light-aircraft drop test with high-speed belt turn. Based on a drop test under initial parameters to get the friction between the tire and platform, and the elastic parameters of the wheel to simulate the interactions of components, the simulation models are repeatedly modified by analyzing the results of comparisons between drop test and simulation. Thus, an accurate model is established with optimal parameters, which verifies that the shock-absorbing properties of the landing gear with the optimal parameters meet the requirements of airworthiness rules, and the properties are greatly improved. According to the requirement of China Civil Aviation Regulations Order No. 132 (CCAR-23-R3) and the application of virtual prototype technology for the light multifunctional amphibious airplane, the adjusting-parameter drop test, the limited drop test, and the reserve-energy absorption drop test of the nose landing gear are accomplished. The limited load measured in the test is less than the design load, and the landing gear can bear the reserve-energy absorption drop test. The study shows that the adjusting-parameter drop test for establishing a simulation model is an available and reliable way to optimize the shock-absorbing properties of an amphibious-aircraft landing gear. The test system can be applied for the landing-gear drop-test of other light airplanes. Moreover, the test results can be used as the certification of the airworthiness for this airplane.Nomenclature A a = area where the piston rod squeezes out the air (except for the oil-hole area) A h = area where the piston rod squeezes out the oil (except for the oil-hole area) A 0 = sectional area of oil hole a t = acceleration of hanging basket C d = flow coefficient of the oil hole C = vertical damping coefficient of the wheel d m = diameter of the main oil hole d s = diameter of one-way oil hole F m t = total friction force between platform and the four supported pillars F x = horizontal load acting on the wheel F Y t = vertical load of the wheel F z = vertical load acting on the wheel K = vertical deformation coefficient of the wheel k va = calibration value of vertical acceleration sensor fixed on platform. k vg = calibration value of vertical load sensor M 1 = mass of platform N = number of wheel N Y t = inertia force of platform n n = inertial overload coefficient P S = atmospheric pressure P y t = resultant force measured by four sensors P 0 = initial pressure of buffer pt = tension-compression load of platform in the drop test S = stroke of buffer S max = maxi...

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Section: Nomenclaturementioning

confidence: 99%

Landing-Gear Drop-Test Rig Development and Application for Light Airplanes

Xue

Han

Wengang

et al. 2012

Journal of Aircraft

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“…Lernbeiss introduced a multi-body system-based landing gear model for numerical simulation of simple static and dynamic load conditions and successfully correlated the simulation results with the outcomes of a more accurate finite element simulation [16]. The Lernbeiss model was then revised and improved by Kong, based on drop-impact analysis and experiments conducted on a smart UAV landing system [17]. LMS ® analysis software for multi-body dynamics was used by Xue and Yu to build a coupled rigid-flexible simulation model of light aircraft main landing gear, showing very good capability in terms of drop-test load estimation [18].…”

Section: Introductionmentioning

confidence: 99%

A Rational Numerical Method for Simulation of Drop-Impact Dynamics of Oleo-Pneumatic Landing Gear

Pecora

2021

Applied Sciences

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Oleo-pneumatic landing gear is a complex mechanical system conceived to efficiently absorb and dissipate an aircraft’s kinetic energy at touchdown, thus reducing the impact load and acceleration transmitted to the airframe. Due to its significant influence on ground loads, this system is generally designed in parallel with the main structural components of the aircraft, such as the fuselage and wings. Robust numerical models for simulating landing gear impact dynamics are essential from the preliminary design stage in order to properly assess aircraft configuration and structural arrangements. Finite element (FE) analysis is a viable solution for supporting the design. However, regarding the oleo-pneumatic struts, FE-based simulation may become unpractical, since detailed models are required to obtain reliable results. Moreover, FE models could not be very versatile for accommodating the many design updates that usually occur at the beginning of the landing gear project or during the layout optimization process. In this work, a numerical method for simulating oleo-pneumatic landing gear drop dynamics is presented. To effectively support both the preliminary and advanced design of landing gear units, the proposed simulation approach rationally balances the level of sophistication of the adopted model with the need for accurate results. Although based on a formulation assuming only four state variables for the description of landing gear dynamics, the approach successfully accounts for all the relevant forces that arise during the drop and their influence on landing gear motion. A set of intercommunicating routines was implemented in MATLAB® environment to integrate the dynamic impact equations, starting from user-defined initial conditions and general parameters related to the geometric and structural configuration of the landing gear. The tool was then used to simulate a drop test of a reference landing gear, and the obtained results were successfully validated against available experimental data.

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